They left to found a startup called MemSQL, which is taking on
giant Oracle with a faster, cheaper database. He was 25.

MemSQL offers a commercial version similar to the database that
Facebook built for itself. (Before Facebook, Shamgunov also
helped Microsoft build its database competitor to Oracle,
Microsoft's SQL Server).

It was hard to leave Facebook and the financial comforts it
held, Frenkiel told Business Insider. And his friends and
family told him he was crazy to consider it. But he left anyway.

"I’ve always believed that you always regret what you didn’t do,
not what you did. I knew if I hadn't done this decision, I’d
always kick myself," said Frenkiel, the now 28-year-old CEO of
MemSQL.

But even from the start, there were signs that MemSQL could be a
big success. For instance, it's the first enterprise company
accepted into the Ycombinator program, he told us.

Plus, the tech is in a hot enterprise area called the "in-memory
database," meaning that all of the data is stored in RAM, not on
hard disks. SAP is having big success taking on Oracle with its
in-memory database called HANA. But MemSQL runs on ordinary,
low-cost commodity servers, and doesn't need the expensive
specialized hardware that Oracle sells.

Frenkiel is careful not to say that MemSQL will one day put the
mighty Oracle out of business. He believes there's plenty of room
for new database startups and the traditional players, thanks to
the "big data" trend.

But he also says that MemSQL on an ordinary server costs about
$4,000 per terabyte of data stored, whereas Oracle's latest
database, with its new in-memory feature on one of Oracle's
specially built servers, can run $100,000 per terabyte stored.

And that's why, in two years, the company has snagged some
impressive customers like Comcast, Morgan Stanley, Zynga and
ShutterStock.